1. Field of the Invention
The invention relates to a process for producing a decoration, in particular a wood decoration, and a relief, corresponding to the decoration, at least on the top side of a woodbased-material board which is pressed in a press, by means of a pressing plate, with a cover layer which consists of a synthetic resin and has been applied beforehand to the top side, the relief being stamped, during the pressing operation, by a female die which interacts with the pressing plate.
2. Background Description
Such a process is known for the purpose of coating a wood fiberboard (MDF, HDF, chipboard or the like) in order to give it the appearance of a genuine-wood panel. Such boards are then used for furniture construction or for covering walls, ceilings or floors. The desired decoration (woodgrain, parquet, tiling, etc.) is printed onto a paper web, which is then coated with synthetic resin and rolled up on to a roll or set down in sheets. The printed paper is then subsequently applied to a wood fiberboard, if appropriate covered by a layer of synthetic resin and then pressed in a press, under the action of temperature, with the wood fiberboard, in which case the synthetic-resin layer melts. The top pressing plate of the press is designed as a female die and provided with a relief which corresponds to the decoration. During pressing, depressions are then formed in the synthetic-resin layer, and these reproduce, for example, the surface of a wooden board or the joints of laid tiles, in order to form as natural a surface as possible on the woodbased material board.
As a result of the operations of printing the decoration onto the paper web, or subsequently sealing the paper web with synthetic resin and of then connecting the decorative layer to the wood fiberboard by pressure and temperature, the dimensions of the paper web change. According to the person skilled in the art, the paper grows. The paper grows both in length (increase in length) and in width (increase in width). The paper growth cannot be predetermined and is up to 1%. In the case of a conventional press length of 5.6 m, the paper thus grows by more than 5 cm throughout. The female die, which stamps the relief into the synthetic-resin layer, is designed to correspond to the desired structure of the decoration, and it is not possible to make allowances for the paper growth, since the latter cannot be ascertained. In practice, the relief does not match the decoration, as a result of which it is not possible to imitate a genuine-wood surface. The deviations between the decorative structure and relief for example in the case of a tile pattern, as is used for floor panels, have to be assessed even more critically. If the relief which assists the printed-on joint is stamped alongside the joint, rather than on top of it, this results in a grave loss in quality.